Benefits of 6-weeks high-intensity circuit training with or without blood flow restriction on physical fitness in active males: A randomized controlled trial

ABSTRACT Objective To investigate the effects of a 6-weeks 7-min workout (7MW), with and without blood flow restriction (BFR), on physical fitness. Methods Thirty-three active healthy males (age: 23.3 ± 2.6 yr; body mass index: 22.5 ± 1.9 kg·m -2 ) were randomly assigned to 7MW, 7MW-BFR (150 mmHg cuff pressure applied to proximal thighs), or control (CON) groups. 7MW, comprising 12 bodyweight exercises, was performed 3 times per week, with one set during weeks 1–3 and two sets during weeks 4–6. Outcomes included body fat percentage (%BF), thigh circumference (TC), maximal oxygen uptake (VO 2 max), isometric mid-thigh pull variables (peak [PF] and mean [MF] force, and maximal rate of force development [RFDmax]), and countermovement jump (CMJ) height. Results Adjusting for baseline values, post-intervention VO 2 max was higher in 7MW ( p < 0.001, 95% CI: 2.1–5.7 mL·kg -1 ·min -1 ) and 7MW-BFR ( p = 0.002, 95% CI: 1.3–4.9 mL·kg -1 ·min -1 ) than in CON. PF and MF were greater in both training groups than in CON, with larger effects in 7MW-BFR (PF: p < 0.001, d = 1.21, 95% CI: 155–451 N; MF: p < 0.001, d = 1.15, 95% CI: 142–448 N) than in 7MW (PF: p = 0.030, d = 0.63, 95% CI: 17–315 N; MF: p = 0.026, d = 0.68, 95% CI: 23–332 N). No significant changes were observed in %BF, TC, RFDmax, or CMJ height. Conclusions The 7MW-based program can improve aerobic capacity and muscular strength in active males, and BFR may further augment strength gains.